# AoC 2017 Day 4: Password Validator

### Source: High-Entropy Passphrases

Part 1: Given a list of passphrases, count how many contain no duplicate words.

# AoC 2016 Day 7: IPv7 Support Counter

### Source: Internet Protocol Version 7

Part 1: The input is a list of strings, potentially containing sequences in square brackets. Find all strings that have an ABBA sequence (two characters followed by the same two in reverse order) outside of any square brackets, but no ABBA sequences in square brackets.

# AoC 2016 Day 4: Room Validator

### Source: Security Through Obscurity1

Part 1: A room is described as a name, a sector ID, and a checksum as follows:

aaaaa-bbb-z-y-x-123[abxyz]

name: aaaaa-bbb-z-y-x sector ID: 123 checksum: abxyz

# Number words

Today’s five minute post brought to you via Programming Praxis / Career Cup:

Given a positive integer, return all the ways that the integer can be represented by letters using the mapping 1 -> A, 2 -> B, …, 26 -> Z. For instance, the number 1234 can be represented by the words ABCD, AWD and LCD.

"#\u043f\u043e\u0431\u0435\u0434\u0430\u0437\u0430\u043d\u0430\u043c\u0438"